Designjet 500ps 79:04 error

[taskalfa]

Hi HP experts , I’m getting this error on a 500ps, printer starts up and then comes up with 79:04 firmware error, initially the printer came in for a 02:10 error, when I pulled it apart i noticed that the trailing cables had been damaged , once we replaced cables that’s when the 79:04 error appeared , I managed to update firmware by entering service menu but still error persists, any help appreciated
i have also tried the carriage assembly pcb, no luck

[Kiran Otter]

Have you tried it with any accessory cards removed? Network, hard drive, HPGL2, etc.

If you disconnect the trailing cable and turn it on, do you get an 11:11?

When does the 79:04 occur?

Kiran

[Tech1]

I've seen 79 errors caused by faulty or expired printheads. Try removing all of them and reinstalling one at a time when prompted.

[taskalfa]

Have you tried it with any accessory cards removed? Network, hard drive, HPGL2, etc.

If you disconnect the trailing cable and turn it on, do you get an 11:11?

When does the 79:04 occur?

Kiran

Yes if trailing cable is out it will throw a 11::11 code, if I leave out the inkheads it still aligns the carriage assembly and then displays error 79:04 , it doesn’t ask for inkheads

[Kiran Otter]

Maybe you have the service station installed incorrectly? Try removing it but keep it plugged in, and see if the printer starts up correctly.

The service station has to sit on two ledges when you slide it in, and don't put washers under the two screws.

If it's not that, if you can take a video of it starting up and share it with dropbox or something, that would be helpful.

Kiran

[taskalfa]

Maybe you have the service station installed incorrectly? Try removing it but keep it plugged in, and see if the printer starts up correctly.

The service station has to sit on two ledges when you slide it in, and don't put washers under the two screws.

If it's not that, if you can take a video of it starting up and share it with dropbox or something, that would be helpful.

Kiran

Thanks, I will work on it tomorrow and see how it goes, I will try and upload a video of what is happening

[taskalfa]

Hi, this is the link to view the printer starting up
IMG_9845.MOV - Google Drive

The only thing to replace next would be the electronics ?

[Kiran Otter]

Is it turning the roller when the error occurs? Did you disconnect any of the wires to the electronics module?

At the point it appears to throw the error, it should be checking the drive roller/motor by advancing the paper a ways, then rolling it back, then the printer will move the carriage to check the paper width. So it's crashing while checking the roller motor and encoder. So either the motor is connected backwards, or the encoder is not connected correctly. I think there's 2 connections that look the same; make sure they're not swapped. Of course if you didn't touch any of that and the printer worked beforehand, that's not the problem.

Kiran